She has apparently farmed out her kids to relatives so she can be with Josh all the time. I do not think itis to help out Ms. Rieber. I think its because she believes her place is by her husband's side. The kids don't need care, he does in her worldview. The whole "make oneself joyfully available" at all times thing. Since he's not in the same house she has to be where he is.
If she were really a good mom, but just unwilling to divorce Josh, him living with the Riebers would be the perfect excuse to avoid him. " Oh I have to care for all these kids, I just can't be running ove